(INDIANAPOLIS) — The parents of American aid worker Peter Kassig released a video statement to their son on Saturday, expressing concern and calling for militant group ISIS to “show mercy.”

Kassig, a 26-year-old Indiana native, is seen at the end of the most recent ISIS video released Friday, which showed the apparent death of British captive Alan Henning.

“Know that we love you, and our hearts ache for you to be granted your freedom so we can hug you again and then set you free to continue the life you have chosen, the life of service to those in greatest need,” mother Paula Kassig said in Saturday’s message. “We implore those who are holding you to show mercy and use their power to let you go.”

Kassig, who has taken on the first name Abdul-Rahman, according to the family, is an Army veteran who served in the Iraq war. He was honorably discharged for medical reasons and later went on to work as an emergency medical technician and volunteer medical assistance in border hospitals in Lebanon.

He was abducted in 2013 while traveling in eastern Syria for a a non-governmental organization he founded and converted to Islam while being held hostage, according to a family spokesperson. Kassig converted “of his own free will,” the representative added, saying that prior to his captivity, he had fasted during Ramadan with friends and colleagues.

“The driving force in our family has always been to serve others. Our son comes from two long lines of teachers and humanitarian workers,” his father, Ed Kassig, said Saturday. “Our family deplores all human suffering and the loss of innocent life, no matter who is responsible.

“We respond by trying to provide aid and assistance. Our son was living his life according to that same humanitarian call when he was taken captive.

We know that Syrians are suffering. We also believe violence is not the solution to the problems that trouble us all. There is so much that is beyond our control. We asked our government to change its actions, but like our son, we have no more control over the U.S. government than you have over the break of dawn.

We implore his captors to show mercy and use their power to let our son go.”